1. Field of the Invention:
This invention relates to animal feed supplements for ruminants. More specifically, the invention relates to extruded animal feed nuggets which function as a rumen escape composition and permit the release of beneficial nutrients in the abomasum or subsequent digestive tract. In one aspect, the invention relates to extruded animal feed nuggets suitable for consumption by ruminants. In another aspect, the invention relates to a method of making an extruded animal feed nugget using conventional extrusion equipment. In still another aspect, the invention relates to finished feed products of which the extruded animal feed nugget is a component. In a further aspect, this invention relates to a method of achieving the same level of milk and milk component yield in ruminants which are fed a lower crude protein diet than those which are fed a normal crude protein diet.
2. Description of the Prior Art:
In ruminant animals, such as cattle and sheep, microorganisms in the rumen are responsible for degrading most biologically active substances, such as proteins and amino acids. This microbial intervention inhibits the provision of supplemental nutrients to the ruminant because many desirable nutrients are metabolized before they reach a site where they can be absorbed and utilized by the host animal. Accordingly, it is important to pass these biologically active substances through the rumen without decomposition by microorganisms to allow their effective digestion and absorption in the abomasum and subsequent digestive tract.
Many techniques, formulations and the like have been tried in the past to protect the biologically active substances from further degradation in the rumen. In U.S. Pat. No. 4,248,899 to Lyon, et al., a feed supplement is prepared from protein extracted from a leafy green source. The protein is then combined with a triglyceride lipid material. U.S. Pat. Nos. 5,145,695 and 5,219,596 to Smith, et al. disclose a feed formulation of dairy feedstuffs which is balanced to deliver necessary amino acid requirements at a particular point in a cow's digestive system.
Another method involves utilizing the difference in pH between the rumen and the abomasum by coating the feed with a polymer which is insoluble in the environment of the rumen but is soluble in the strongly acidic abomasum. Still another method, disclosed in U.S. Pat. No. 5,227,166 to Ueda, et al., involves coating a core of biologically active substances with lecithin, at least one inorganic substance which is stable at a neutral pH and soluble under acidic conditions, and at least one substance selected from the group consisting of straight-chain or branched-chain saturated or unsaturated monocarboxylic acids and salts having 14 to 22 carbon atoms, hardened vegetable oils, hardened animal oils and waxes.
While effective to one degree or another, these methods generally require extensive processing and/or expensive reagents. As such, simplified and/or more economical methods for supplying sufficient quantities of essential amino acids for absorption in the small intestines remain of interest to the ruminant feed industry.